This invention relates to photoreceptor substrates. More particularly, this invention relates to methods of lathing and cleaning photoreceptor substrates.
Many electrophotographic copiers, digital copiers, laser printers, and the like contain an electrophotographic photoreceptor wherein a photoconductive layer is provided on a rotatable drum-like substrate. The substrate may be made by machining the surface of a pipe, and a cutting fluid is normally used in this process. The cutting fluid is used to cool, lubricate, and clean the substrate. Many current processes for machining photoreceptor substrates use a petroleum-based cutting fluid.
For inspection purposes and to prepare the substrates for final cleaning and coating of photoconductor layers, the substrates are cleaned after machining to remove residual cutting fluid. Typically, petroleum residues on a substrate are removed by methods using an ultrasonic vapor degreaser with a chlorine solvent, such as, for example, 1,1,1-trichloroethane, trichloroethylene, perchloroethylene, methylene chloride, and the like. However, the use of such solvents can cause problems of environmental contamination and working safety from the viewpoint of ozone layer destruction, carcinogenicity and the like.
Alternatives to chlorine-containing solvents include aliphatic hydrocarbons such as kerosene or strong acid-based detergents. However, these alternatives can present new problems including fire risks and waste neutralization.
A preferred alternative to chlorine solvents would be a neutral aqueous cleaner. A number of commercial aqueous cutting fluids which are cleaned with neutral aqueous cleaners have been found to be unsatisfactory. A major problem with these cutting fluids is that they either attack metal on the substrate surface or alter the substrate surface chemistry, especially with aluminum substrates, so that the substrate has the undesirable characteristic of wetting after subseguent cleaning.